Sewage systems are in universal use for removal of waste materials from individual dwellings, industrial premises, and municipalities. Waste materials are commonly carried by means of water flowing through pipes or conduits to sewage treatment plants. To maintain flow rate, sewage pumps are widely used. These pumps are electrically operated and are often automatically operated by use of float switches, proximity switches, probes, or the like. For example, when waste material/fluid in a wet well located at a sewage pump or lift station reaches a predetermined level, the pumps operate to empty the well. When waste material/fluid in the well falls to a second predetermined level, the pumps cease operation. Sewage contains various substances, such as waste, fats, greases, grit, and slime, which are capable of damaging the internal surfaces of, e.g., wet wells as well as the machinery located therein. As sewage levels decrease during pump operation, a residue of fats and other substances is left on the walls of the well between the high and low liquid levels. This residue, if allowed to accumulate, may damage machinery such as pumps, as well as causing damage to the walls of the well itself.
Another issue facing sewage treatment/storage systems is odor. It is not feasible to create a sewage treatment system in which sewage is constantly moving to its final destination. At certain points in all sewage treatment systems, sewage must be temporarily stored or accumulated prior to being moved to its next destination. Storage or retention of waste in holding tanks, wet wells, etc., even for a relatively short period of time, results in formation of significant odor, primarily due to hydrogen sulfide gases. Odors associated with sewage, such as from hydrogen sulfide, cause complaints in neighboring communities and municipalities, and may create a health hazard.
Accordingly, residue left by pumping operations in sewage pump or lift station facilities such as wet wells, sump wells, sumps, collection tanks, holding tanks, and the like must be removed. In many sewage systems, the process of cleaning this residue must be accomplished manually, requiring closed space entry into the well or tank by maintenance personnel. Due to odor, gas formation, slippery surfaces, and the like such closed space entry is at minimum unpleasant, and may pose a health hazard to personnel.
Accordingly, there is need in the art for cleaning systems capable of cleaning the interior of containers such as wet wells, holding tanks, and the like, to prevent the need for closed space entry into sewage holding facilities by humans. There is further need in the art for such cleaning systems which are also capable of ameliorating the odor associated with sewage holding containers during and between cleaning cycles.